Systems and methods for providing seamless software compatibility using virtual machines

ABSTRACT

Certain embodiments of the present invention are directed to a system for and method of providing seamless software compatibility by using virtual machines to provide an improved, more seamless method of user interaction with one or more virtual machines (VMs) that are resident on a host computer system. Several embodiments of the present invention provide a means in the host environment for directly invoking one or more guest operating system (OS) applications or files and displaying them in the host environment, rather than in a separate VM window. Furthermore, each embodiment of the present invention allows the possibility of multiple applications on multiple OSs (i.e., legacy or modem OSs), respectively, to run simultaneously and with the appearance of running seamlessly in the host environment.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/883,491, filed on Jun. 30, 2004, the entire contents of which areincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to the field virtual machines(also known as “processor virtualization”) and software that executes ina virtual machine environment. More specifically, the present inventionis directed to providing seamless execution of a software applicationwritten for a first operating system on a second operating system usinga using virtual machine.

BACKGROUND OF THE INVENTION

Computers include general purpose central processing units (CPUs) thatare designed to execute a specific set of system instructions. A groupof processors that have similar architecture or design specificationsmay be considered to be members of the same processor family. Examplesof current processor families include the Motorola 680X0 processorfamily, manufactured by Motorola, Inc. of Phoenix, Ariz.; the Intel80X86 processor family, manufactured by Intel Corporation of Sunnyvale,Calif.; and the PowerPC processor family, which is manufactured byMotorola, Inc. and used in computers manufactured by Apple Computer,Inc. of Cupertino, Calif. Although a group of processors may be in thesame family because of their similar architecture and designconsiderations, processors may vary widely within a family according totheir clock speed and other performance parameters (or capabilities).

Each family of microprocessors executes instructions that are unique tothe processor family. The collective set of instructions that aprocessor or family of processors can execute is known as theprocessor's instruction set. As an example, the instruction set used bythe Intel 80X86 processor family is incompatible with the instructionset used by the PowerPC processor family. The Intel 80X86 instructionset is based on the Complex Instruction Set Computer (CISC) format. TheMotorola PowerPC instruction set is based on the Reduced Instruction SetComputer (RISC) format. CISC processors use a large number ofinstructions, some of which can perform rather complicated functions,but which require generally many clock cycles to execute. RISCprocessors use a smaller number of available instructions to perform asimpler set of functions that are executed at a much higher rate.

The uniqueness of the processor family among computer systems alsotypically results in incompatibility among the other elements ofhardware architecture of the computer systems. A computer systemmanufactured with a processor from the Intel 80X86 processor family willhave a hardware architecture that is different from the hardwarearchitecture of a computer system manufactured with a processor from thePowerPC processor family. Because of the uniqueness of the processorinstruction set and a computer system's hardware architecture,application software programs are typically written to run on aparticular computer system running a particular operating system.

Computer manufacturers want to maximize their market share by havingmore rather than fewer applications run on the microprocessor familyassociated with the computer manufacturers' product line. To expand thenumber of operating systems and application programs that can run on acomputer system, a field of technology has developed in which a givencomputer having one type of CPU, called a host, will include an emulatorprogram that allows the host computer to emulate the instructions of anunrelated type of CPU, called a guest. Thus, the host computer willexecute an application that will cause one or more host instructions tobe called in response to a given guest instruction. Thus the hostcomputer can both run software design for its own hardware architectureand software written for computers having an unrelated hardwarearchitecture. As a more specific example, a computer system manufacturedby Apple Computer, for example, may run operating systems and programwritten for PC-based computer systems. It may also be possible to use anemulator program to operate concurrently on a single CPU multipleincompatible operating systems. In this arrangement, although eachoperating system is incompatible with the other, an emulator program canhost one of the two operating systems, allowing the otherwiseincompatible operating systems to run concurrently on the same computersystem.

When a guest computer system is emulated on a host computer system, theguest computer system is said to be a “virtual machine” as the guestcomputer system only exists in the host computer system as a puresoftware representation of the operation of one specific hardwarearchitecture. The terms emulator, virtual machine, and processoremulation are sometimes used interchangeably to denote the ability tomimic or emulate the hardware architecture of an entire computer system.As an example, the Virtual PC software created by Connectix Corporationof San Mateo, Calif. emulates an entire computer that includes an Intel80X86 Pentium processor and various motherboard components and cards.The operation of these components is emulated in the virtual machinethat is being run on the host machine. An emulator program executing onthe operating system software and hardware architecture of the hostcomputer, such as a computer system having a PowerPC processor, mimicsthe operation of the entire guest computer system.

The emulator program acts as the interchange between the hardwarearchitecture of the host machine and the instructions transmitted by thesoftware running within the emulated environment. This emulator programmay be a host operating system (OS), which is an operating systemrunning directly on the physical computer hardware. Alternately, theemulated environment might also be a virtual machine monitor (VMM) whichis a software layer that runs directly above the hardware and whichvirtualizes all the resources of the machine by exposing interfaces thatare the same as the hardware the VMM is virtualizing (which enables theVMM to go unnoticed by operating system layers running above it). A hostoperating system and a VMM may run side-by-side on the same physicalhardware.

Typically, within the host computer system which is emulating one ormore VMs, there is no direct mechanism in the host environment, such asan icon on the desktop, to launch or in some way interact withapplications that are running on any given VM. Rather, a VM is presentedto the user on the host computer system in a separate window thatdisplays the desktop of the guest OS in its native environment, whetherit is a legacy or modem OS. Consequently, the user sees a completelyseparate desktop (e.g., with a separate task bar, “My Computer,” StartMenu, etc.) from that of the host computer system. Using this separateVM window, the user may navigate within the guest OS to launch any VMapplication which, when launched, is likewise displayed in the same VMwindow. If the host computer system is hosting multiple VMs, the desktopof each VM will appear in its own separate window. As a result, in orderfor the user to interact with each VM, the user must navigate from oneVM window to the next. It is cumbersome for the user to navigate fromthe host desktop to one or more separate VM desktops to invoke host orVM applications simultaneously, as the user must continuously swapbetween one window and another and must keep track of what applicationis running in which window. What is needed is a direct mechanism in thehost environment for invoking one or more guest OS applications anddisplaying them in the host environment alongside and interspersed withthe host computer system's applications, rather than in a separate VMwindow, and thereby provide the user with an improved, more seamlessmethod of interacting with one or more VMs resident on a host computersystem.

SUMMARY OF THE INVENTION

Certain embodiments of the present invention are directed to a systemfor and method of providing seamless software compatibility by usingvirtual machines to provide an improved, more seamless method of userinteraction with one or more VMs that are resident on a host computersystem. Several embodiments of the present invention provide a means inthe host environment for directly invoking one or more guest OSapplications and displaying them in the host environment, rather than ina separate VM window. Consequently, the guest operating system desktopis no longer visible. Instead, the individual guest applications windowsappear alongside and interspersed with the host computer system'swindows and, potentially, windows from other virtual machines that arerunning simultaneously, and all of the guest operating systemfunctionality is integrated directly into the host operating systemdesktop (e.g., desktop icons and menu items in the Start Menu forlaunching applications from the desktop, etc.).

A first embodiment of the invention comprises a plurality of applicationproxies that are visible to the user in the host environment and anapplication launch layer resident in the host OS. Each application proxyis associated with a host or VM application. The function of theapplication launch layer is to identify whether the given applicationproxy is launching a host or VM application. The application launchlayer then communicates to either the host OS or the VMM, respectively,to take the necessary action to launch the user-selected application. Inthe case of a VM application, the application launch layer communicatesto the VMM to launch a VM with its associated guest OS, whichsubsequently launches the VM application.

In an alternative embodiment, the invention comprises a plurality ofapplication files that are visible to the user in the host environmentalongside and interspersed with the host files via a file integrationlayer resident in the host OS. Each application file is associated witha host or VM application. The function of the file integration layer isto allow the user to directly interact with either a host or VMapplication, for example, to launch the user-selected application.

Furthermore, each embodiment of the present invention allows thepossibility of multiple applications on multiple OSes (i.e., legacy ormodern OSes), respectively, to run simultaneously and with theappearance of running seamlessly in the host environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, there is shown in the drawings exemplary constructions of theinvention; however, the invention is not limited to the specific methodsand instrumentalities disclosed. In the drawings:

FIG. 1 is a block diagram representing a computer system in whichaspects of the present invention may be incorporated;

FIG. 2 illustrates the logical layering of the hardware and softwarearchitecture for an emulated operating environment in a computer system;

FIG. 3A illustrates a virtualized computing system;

FIG. 3B illustrates an alternative embodiment of a virtualized computingsystem comprising a virtual machine monitor running alongside a hostoperating system;

FIG. 4A illustrates a host display window showing a conventional way ofvisually presenting a guest application window to a user as a separatewindow within host display window;

FIG. 4B illustrates a host display window visually presenting a guestdesktop icon and guest application window to a user within the hostdisplay window as if guest application window is part of the native OSenvironment;

FIG. 4C illustrates a host display window visually presenting a guestdesktop icon and guest application window to a user within the hostdisplay window as if guest application window is part of the native OSenvironment, as well as (at the user's option) the host display windowalso displaying a window for the guest operating system and its activecomponents;

FIG. 5 is a block diagram that represents portions of the system of FIG.3B in a first embodiment of the invention and further comprises aplurality of application proxies and an application launch layer;

FIG. 6 is a flowchart that illustrates a method of providing and usingan application proxy for launching a VM application in a hostenvironment;

FIG. 7A illustrates host display window showing a conventional way ofvisually presenting a guest file tree to a user in a separate windowwithin host display window;

FIG. 7B illustrates host display window visually presenting a compositefile tree, which is the combination of a host file tree and a guest filetree, to a user within host display window as if guest file tree is partof the native OS environment;

FIG. 8 is a block diagram that represents portions of the system of FIG.3B in a second embodiment of the invention and further comprises aplurality of application files within an integrated file system; and

FIG. 9 is a flowchart that illustrates a method of providing and usingan integrated file system for interacting with a VM application in ahost environment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The inventive subject matter is described with specificity to meetstatutory requirements. However, the description itself is not intendedto limit the scope of this patent. Rather, the inventor has contemplatedthat the claimed subject matter might also be embodied in other ways, toinclude different steps or combinations of steps similar to the onesdescribed in this document, in conjunction with other present or futuretechnologies. Moreover, although the term “step” may be used herein toconnote different elements of methods employed, the term should not beinterpreted as implying any particular order among or between varioussteps herein disclosed unless and except when the order of individualsteps is explicitly described.

Computer Environment

Numerous embodiments of the present invention may execute on a computer.FIG. 1 and the following discussion is intended to provide a briefgeneral description of a suitable computing environment in which theinvention may be implemented. Although not required, the invention willbe described in the general context of computer executable instructions,such as program modules, being executed by a computer, such as a clientworkstation or a server. Generally, program modules include routines,programs, objects, components, data structures and the like that performparticular tasks or implement particular abstract data types. Moreover,those skilled in the art will appreciate that the invention may bepracticed with other computer system configurations, including hand helddevices, multi processor systems, microprocessor based or programmableconsumer electronics, network PCs, minicomputers, mainframe computersand the like. The invention may also be practiced in distributedcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed computing environment, program modules may be located inboth local and remote memory storage devices.

As shown in FIG. 1, an exemplary general purpose computing systemincludes a conventional personal computer 20 or the like, including aprocessing unit 21, a system memory 22, and a system bus 23 that couplesvarious system components including the system memory to the processingunit 21. The system bus 23 may be any of several types of bus structuresincluding a memory bus or memory controller, a peripheral bus, and alocal bus using any of a variety of bus architectures. The system memoryincludes read only memory (ROM) 24 and random access memory (RAM) 25. Abasic input/output system 26 (BIOS), containing the basic routines thathelp to transfer information between elements within the personalcomputer 20, such as during start up, is stored in ROM 24. The personalcomputer 20 may further include a hard disk drive 27 for reading fromand writing to a hard disk, not shown, a magnetic disk drive 28 forreading from or writing to a removable magnetic disk 29, and an opticaldisk drive 30 for reading from or writing to a removable optical disk 31such as a CD ROM or other optical media. The hard disk drive 27,magnetic disk drive 28, and optical disk drive 30 are connected to thesystem bus 23 by a hard disk drive interface 32, a magnetic disk driveinterface 33, and an optical drive interface 34, respectively. Thedrives and their associated computer readable media provide non volatilestorage of computer readable instructions, data structures, programmodules and other data for the personal computer 20. Although theexemplary environment described herein employs a hard disk, a removablemagnetic disk 29 and a removable optical disk 31, it should beappreciated by those skilled in the art that other types of computerreadable media which can store data that is accessible by a computer,such as magnetic cassettes, flash memory cards, digital video disks,Bernoulli cartridges, random access memories (RAMs), read only memories(ROMs) and the like may also be used in the exemplary operatingenvironment.

A number of program modules may be stored on the hard disk, magneticdisk 29, optical disk 31, ROM 24 or RAM 25, including an operatingsystem 35, one or more application programs 36, other program modules 37and program data 38. A user may enter commands and information into thepersonal computer 20 through input devices such as a keyboard 40 andpointing device 42. Other input devices (not shown) may include amicrophone, joystick, game pad, satellite disk, scanner or the like.These and other input devices are often connected to the processing unit21 through a serial port interface 46 that is coupled to the system bus,but may be connected by other interfaces, such as a parallel port, gameport or universal serial bus (USB). A monitor 47 or other type ofdisplay device is also connected to the system bus 23 via an interface,such as a video adapter 48. In addition to the monitor 47, personalcomputers typically include other peripheral output devices (not shown),such as speakers and printers. The exemplary system of FIG. 1 alsoincludes a host adapter 55, Small Computer System Interface (SCSI) bus56, and an external storage device 62 connected to the SCSI bus 56.

The personal computer 20 may operate in a networked environment usinglogical connections to one or more remote computers, such as a remotecomputer 49. The remote computer 49 may be another personal computer, aserver, a router, a network PC, a peer device or other common networknode, and typically includes many or all of the elements described aboverelative to the personal computer 20, although only a memory storagedevice 50 has been illustrated in FIG. 1. The logical connectionsdepicted in FIG. 1 include a local area network (LAN) 51 and a wide areanetwork (WAN) 52. Such networking environments are commonplace inoffices, enterprise wide computer networks, intranets and the Internet.

When used in a LAN networking environment, the personal computer 20 isconnected to the LAN 51 through a network interface or adapter 53. Whenused in a WAN networking environment, the personal computer 20 typicallyincludes a modem 54 or other means for establishing communications overthe wide area network 52, such as the Internet. The modem 54, which maybe internal or external, is connected to the system bus 23 via theserial port interface 46. In a networked environment, program modulesdepicted relative to the personal computer 20, or portions thereof, maybe stored in the remote memory storage device. It will be appreciatedthat the network connections shown are exemplary and other means ofestablishing a communications link between the computers may be used.Moreover, while it is envisioned that numerous embodiments of thepresent invention are particularly well-suited for computerized systems,nothing in this document is intended to limit the invention to suchembodiments.

Virtual Machines (VMs)

From a conceptual perspective, computer systems generally comprise oneor more layers of software running on a foundational layer of hardware.This layering is done for reasons of abstraction. By defining theinterface for a given layer of software, that layer can be implementeddifferently by other layers above it. In a well-designed computersystem, each layer only knows about (and only relies upon) the immediatelayer beneath it. This allows a layer or a “stack” (multiple adjoininglayers) to be replaced without negatively impacting the layers abovesaid layer or stack. For example, software applications (upper layers)typically rely on lower levels of the operating system (lower layers) towrite files to some form of permanent storage, and these applications donot need to understand the difference between writing data to a floppydisk, a hard drive, or a network folder. If this lower layer is replacedwith new operating system components for writing files, the operation ofthe upper layer software applications remains unaffected.

The flexibility of layered software allows a virtual machine (VM) topresent a virtual hardware layer that is in fact another software layer.In this way, a VM can create the illusion for the software layers aboveit that said software layers are running on their own private computersystem, and thus VMs can allow multiple “guest systems” to runconcurrently on a single “host system.”

FIG. 2 is a diagram representing the logical layering of the hardwareand software architecture for an emulated operating environment in acomputer system. An emulation program 94 runs on a host operating systemand/or hardware architecture 92. Emulation program 94 emulates a guesthardware architecture 96 and a guest operating system 98. Softwareapplication 100 in turn runs on guest operating system 98. In theemulated operating environment of FIG. 2, because of the operation ofemulation program 94, software application 100 can run on the computersystem 90 even though software application 100 is designed to run on anoperating system that is generally incompatible with the host operatingsystem and hardware architecture 92.

FIG. 3A illustrates a virtualized computing system comprising a hostoperating system software layer 104 running directly above physicalcomputer hardware 102, and the host operating system (host OS) 104virtualizes all the resources of the machine by exposing interfaces thatare the same as the hardware the host OS is virtualizing (which enablesthe host OS to go unnoticed by operating system layers running aboveit).

Alternately, a virtual machine monitor, or VMM, software layer 104′ maybe running in place of or alongside a host operating system 104″, thelatter option being illustrated in FIG. 3B. For simplicity, alldiscussion hereinafter (specifically regarding the host operating system104) shall be directed to the embodiment illustrated in FIG. 3A;however, every aspect of such discussion shall equally apply to theembodiment of FIG. 3B wherein the VMM 104′ of FIG. 3B essentiallyreplaces, on a functional level, the role of the host operating system104 of FIG. 3A described herein below.

Referring again to FIG. 3A, above the host OS 104 (or VMM 104′) are twovirtual machine (VM) implementations, VM A 108, which may be, forexample, a virtualized Intel 386 processor, and VM B 110, which may be,for example, a virtualized version of one of the Motorola 680X0 familyof processors. Above each VM 108 and 110 are guest operating systems(guest OSs) A 112 and B 114 respectively. Above guest OS A 112 arerunning two applications, application A1 116 and application A2 118, andabove guest OS B 114 is Application B1 120.

Host OS and VM Application Integration

FIG. 4A illustrates a host display window 122 of host OS 104″showing aconventional way of visually presenting a guest application window to auser as a separate window within host display window 122. Morespecifically, host display window 122 of host OS 104″ displays anexample host menu bar 124 by which the user may select, for example, the“Start” menu; an example host desktop icon 126 by which the user myopen, for example, the “My Computer” window; a guest display window 128,which represents the visual display of, for example, guest OS A 112 ofVM A 108. Guest display window 128 of guest OS A 112 of VM A 108 furtherdisplays an example guest menu bar 130 by which the user may select, forexample, the “Start” menu of guest OS A 112; an example guest desktopicon 132 by which the user my open, for example, the “My Computer”window of guest OS A 112; and a guest application window 134, which isrepresentative of the application launched via guest desktop icon 132.

Accordingly, to access VM applications, the user must be aware that a VMexists on the host OS, and the user must manually accesses the VM andits associated programs and applications via the separate VM displaywindow, such as illustrated in FIG. 4A.

In contrast, and as illustrated in FIG. 4B, several embodiments of thepresent invention are directed to a host OS presenting in the hostdisplay window 122 a “promoted” guest desktop icon 132′ (promoted upfrom the guest display window 128) to enable a user to directly executethe corresponding guest application program in the VM from the hostdesktop.

For certain embodiments, this promoted guest desktop icon 132′ is fullyintegrated in with the arrangement of existing host desktop icons (e.g.,host desktop icon 126), as shown in FIG. 4B; for certain alternativeembodiments, the promoted guest desktop icon 132′ could also bedisplayed in a different manner, such as by grouping all of the“promoted” icons and appending them the end of the regular icon display,or perhaps by displaying them on the right side of the host displaywindow 122 away and apart from the host desktop icons 126.

In addition, several embodiments of the present invention are alsodirected to “promoting” the guest application window 134′ into the hostdisplay window 122 as if guest application was executing in the nativeOS of host computer. For certain embodiments, this promoted guestapplication window 134′ has the same relative size and same relativeposition in the host display window 122 as the guest application window134 would have had in a guest display window 128, as illustrated in FIG.4B; for certain alternative embodiments, the promoted guest applicationwindow 134′ may have a different relative size and/or a differentrelative position in the host display window 122 as the guestapplication window 134 would have had in a guest display window 128. Ofcourse, certain alternative embodiments of the present invention willincorporate features pertaining to both a promoted guest desktop icon132′ and a promoted guest application window 134′ as illustrated in FIG.4B is taken as a single instance of one such embodiment.

Moreover, for certain alternative embodiments of the present invention,as illustrated in FIG. 4C, where such seamless integration is desirablebut where it may not be desirable for the end-user to be entirelyunaware of the underlying VM (such as, for example, when the end-userprefers to see a guest display window whenever the VM and guestoperating system are executing), the guest display window 128 and itscorresponding components (the guest menu bar 130, the guest desktop icon132, and the guest application window 134) are displayed along with thepromoted guest desktop icon 132′ and/or the promoted guest applicationwindow 134′ as illustrated (where the promoted guest application window134′ is shown as being on top of the guest display window in thisinstance). Where the position of the promoted guest application window134′ in the host display window 122 is related to the position of theguest application window 134 in the guest display window 128, themovement of the promoted guest application window 134′ in the hostdisplay window 122 results in a corresponding movement of the guestapplication window 134 in the guest display window 128 for certainembodiments, and vice versa for certain alternative embodiments, andboth for certain alternative embodiments.

However, directing our attention once again to the embodiments of FIG.4B where the integration is fully seamless and the end-user isessentially unaware of the virtual machine being utilized to execute theprogram corresponding to promoted guest desktop icon 132′ (as such isvisually indistinguishable from any other host desktop icon 126), forthese various embodiments an automated component, illustrated in FIGS. 5and 6, is provided specifically to ensure that an end-user need not bemade aware that VM exists. In this way, a user may launch a legacyapplication running on a VM and the visual presentation of thatapplication is provided to the user in the native OS environment. Forexample, guest desktop icon 132 is an icon for Word 97, which is aWindows 95 application. The user double-clicks on guest desktop icon 132to launch Word 97. Subsequently, the automated component (as describe inFIGS. 5 and 6) takes over without the user's awareness to perform thefollowing general steps:

-   -   1. The user selects the Word 97 icon on the host desktop;    -   2. Host OS 104″ detects that Word 97, which executes in Windows        95, has been selected;    -   3. Host OS 104″ determines that the native OS is, for example,        Windows XP;    -   4. Host OS 104″ loads Windows 95 in a VM without any display        thereof;    -   5. Host OS 104″ loads Word 97 in the Windows 95-VM; and    -   6. Host OS 104″ promotes the display for the Word 97 application        from the Windows 95-VM environment to the native OS environment        of host OS 104″ and seamlessly displays Word 97 to the user        accordingly.

In accordance with a first embodiment of the invention, FIG. 5illustrates host OS 104″ of the system of FIG. 3B that further comprisesan application H1 135, an application launch layer 136 and a pluralityof application proxies that provide an automated mechanism for launchingany host or VM application seamlessly in the host environment. In thisexample, host OS 104″ comprises an application H1 proxy 138 forlaunching application H1 135 of host OS 104″, an application A1 proxy140 for launching application A1 116 of guest OS A 112, an applicationA2 proxy 142 for launching application A2 118 of guest OS A 112, and anapplication B1 proxy 144 for launching application B1 120 of guest OS B114. As known and understood by those skilled in the art, a proxy is asoftware mechanism which passes a request from one computer entity toanother, in this case, from the host OS to the VM.

Application H1 proxy 138, application A1 proxy 140, application A2 proxy142, and application B1 proxy 144 are instantiated, for example, asicons on the desktop or the startup menu of host OS 104″, and therebyprovide to the user a mechanism for launching any application in thehost environment, regardless of whether the application exists on thehost OS or a guest OS. In this way, the use of host and VM applicationproxies within host OS 104″ eliminates the need for the user to open andnavigate separate windows in the host environment that represent thedesktop of each VM by which he/she launches any associated guest OSapplications. When an application proxy is selected by the user, theapplication launch layer 136 provides the mechanism for identifyingwhether the given application proxy is launching a host or VMapplication. Application launch layer 136 then communicates either tohost OS 104″ or to VMM 104′, respectively, to take the necessary actionto launch the user-selected application.

As a result, the user is provided a user-friendly, automated, seamlessmechanism between, for example, host OS 104″ and guest OS A 112 andguest OS B 114, which thus provides the visual appearance of all guestOS applications that exist and execute in the host environment.Application A1 116, application A2 118, and application B1 120 may beeither legacy or modern applications; thus, this embodiment of thepresent invention provides a method of visually integrating anapplication of a legacy OS (e.g., MS-DOS™, Windows 3.X™, Windows 95™,Windows 98™, Windows Me™, Windows NT™, and Windows 2000™) within a hostenvironment, such as Windows XP™. Furthermore, this embodiment of thepresent invention allows the possibility of multiple applications onmultiple OSes, respectively, to run simultaneously and with theappearance of running in the host environment.

The operation of the system of FIG. 5 is described in reference to FIG.6, which is a flowchart that illustrates a method 150 of providing andusing an application proxy in a host environment for launching a VMapplication and visually displaying it in the native host environment.At step 152, the method first comprises the installation of anapplication proxy for each existing host and VM application. As aresult, an icon on the desktop or startup menu of host OS 104″ isprovided to the user as a visual representation in the host environmentof each host or VM application. Consequently, the virtual machine'sdesktop is no longer visible. The VM application proxies appearalongside and interspersed with the host computer system's applicationproxies. Furthermore, the individual VM application proxies appearalongside and interspersed with, potentially, application proxies fromother VMs that are running simultaneously.

At step 154, the user selects a host or VM application to run byclicking on its associated application icon. For example, to launchapplication H1 135 of host OS 104″, the user clicks on the applicationH1 proxy 138 icon. Similarly, to launch application A1 116 of guest OS A112, the user clicks on the application A1 proxy 140 icon.

At step 156, the selected application proxy communicates a request toinitiate its associated application to application launch layer 136 ofhost OS 104″, which subsequently determines (at step 158) whether theapplication is a host or VM application. At step 160, if at step 158 itis determined that the request is a VM application, application launchlayer 136 communicates to VMM 104′ to launch a VM with its associatedguest OS, such as VM A 108 and guest OS A 112 or VM B 110 and guest OS B114. At step 162, the guest OS launches the VM application, such asguest OS A 112 launching application A1 116 or guest OS B 114 launchingapplication B1 120. The application subsequently executes and ispresented visually to the user as though the application were running inthe host environment, even though it is actually executing on a VM. Atstep 164, if at step 158 it is determined that the request is a hostapplication, such as application H1 proxy 138 requesting to launchapplication H1 135, application launch layer 136 communicates to host OS104″ to launch the host application.

Host OS and VM File Integration

In addition to visually integrating applications running in a guestoperating system on a virtual machine into the host operating systemdisplay environment, a similar approach to integration would also beadvantageous in regard to files and other data structures that exist inthe virtual machine, e.g., files that exist on a virtual hard drive(VHD) for a given virtual machine (VM). As known and appreciated bythose of skill in the art, the files of a VHD are logical constructsthat are typically stored as a single file (or, in some cases, as aseries of interrelated files that together comprise the VHD) in somesort of persistent data store (i.e., the hard drive of the hostcomputer), which is discussed more fully herein below. Consequently,while these individual data files stored in the VHD are accessible tothe VM, they are not directly accessible to the host operating system(although the single file on the physical hard drive that corresponds tothe entire VHD volume may be accessible) but must be accessed throughthe VM. Similarly, the VM, which provides an environment to a guest OSsuch that the guest OS is largely unaware that it is executing on a VMand not on physical hardware, is unaware of the files that exist for thehost operating system, and thus executing a VM application to, say, edita host operating system file, is somewhat problematic in the existingart. Therefore, on the one hand it would be advantageous if files on aVHD were seamlessly displayed and accessible to the user through thehost operating system, and it would also be advantageous if the files onthe host operating system were seamlessly accessible to applicationsexecuting in the virtual machine. Several embodiments of the presentinvention are directed to provided such solutions.

FIG. 7A illustrates host display window 122 of host OS 104″ showing aconventional way of visually presenting a guest file tree to a user in aseparate window within host display window 122. More specifically, hostdisplay window 122 of host OS 104″ displays the example host menu bar124 by which the user may select, for example, the “Start” menu; theexample host desktop icon 126 by which the user my open, for example,the “My Computer” window; an example host file tree 166 that may bedisplayed within the host “My Computer” window (not shown); and guestdisplay window 128, which represents the visual display of, for example,guest OS A 112 of VM A 108. Host file tree 166 further includes, forexample, a host folder containing various host application files, suchas a host file A, B, and C.

Guest display window 128 of guest OS A 112 of VM A 108 further displaysan example guest file tree 168 that may be displayed within the guest“My Computer” window (not shown) of guest display window 128. Guest filetree 168 further includes, for example, a guest folder containingvarious guest application files, such as a guest files 1, 2, and 3.Accordingly, the user must be aware that a VM exists, the user thenmanually accesses the VM and its associated files in a separate VMdisplay window, such as illustrated in FIG. 7A.

In contrast, and representative of several embodiments of the presentinvention, FIG. 7B illustrates host display window 122 of host OSvisually presenting a composite file tree 170, which is the combinationof host file tree 166 and guest file tree 168, to a user within hostdisplay window 122 as if guest file tree 168 is part of the native OSenvironment of host OS 104″. Accordingly, an automated component (asdescribe in FIGS. 8 and 9) is provided such that the user is not evenaware that a VM exists. In this way, a user may launch a legacyapplication file residing on a VM and the visual presentation of thatapplication file is provided to the user in the native OS environmentsuch that guest files, for example, guest files 1, 2, and 3, have theappearance of residing on the user's local drive. The automatedcomponent for providing composite file tree 170 is described in furtherdetail in reference to FIGS. 8 and 9.

In regard to certain alternative embodiments of the present invention,FIG. 8 illustrates portions of the system of FIG. 3B that furthercomprise a plurality of emulated devices, in this instance a pluralityof virtual hard drives (VHDs). As known and understood by those skilledin the art, a VHD is a virtualized device, logically equivalent to aphysical hard drive device, that a virtual machine emulates for a guestoperating system. (As used herein, the terms “hard disk,” “hard drive,”and “hard disk drive” may be used interchangeably.) In FIG. 8, VM A 108comprises VHD X 156 and VHD Y 158 which, for example, the virtualmachine may emulate for guest OS A 112 as hard drive “C:” and hard drive“D:” (not shown). Likewise, VM B 110 comprises VHD Z 160 for guest OS B114 as hard drive “C:” (not shown) for that operating system.

In this embodiment, VHD X 156 is implemented as a single data file, afile X 176, on a physical hard disk drive 174 of the computer hardware102; VHD Y 158 is also implemented as a single data file, a file Y 178,on the same physical hard disk drive 174; and VHD Z 160 is alsoimplemented as a single data file, a file Z 180, on the physical harddisk drive 174. Of course, as will be understood and readily appreciatedby those skilled in the art, these VHD representations may be located inseveral files and across separate hard drives or separate computersystems, or they can be something other than a file (for example, atable in a database, a database, or a block of active memory). Moreover,although for the present embodiment all three VHDs are in fact filesmaintained by file system 172 of host OS 104″, in alternativeembodiments, they may be implemented in other ways, such as files orother data structures maintained by the VMM 104′. Nevertheless, in thepresent embodiment, and as illustrated in FIG. 8, VHD X 156, VHD Y 158,and VHD Z 160 are implemented through file system 172 of host OS 104″ asfile X 176, file Y 178, and file Z 180, respectively, on physical harddisk drive 174 of physical computer hardware 102.

In FIG. 8, host OS 104″ further comprises a file integration layer 182that is a software layer that operates somewhere above file system 172and that further comprises a plurality of application files that providea mechanism for interacting with any host or VM application seamlesslyin the host environment. In this example, file integration layer 182 ofhost OS 104″ comprises an application file H1 184 associated withapplication H1 135 of host OS 104″, an application file A1 186associated with application A1 116 of guest OS A 112, an applicationfile A2 188 associated with application A2 118 of guest OS A 112, and anapplication file B1 190 associated with application B1 120 of guest OS B114.

The system of FIG. 8 provides to the user a mechanism in the hostenvironment for collectively viewing all files associated with VHDs 156,158, and 160 and hard disk drive 174 of computer hardware 102 in acommingled fashion, regardless of whether the files associate with thehost or a VM. For example, application file H1 184, application file A1186, application file A2 188, and application file B1 190 are allvisible to the user in the “My Computer” or “Explore” windows of host OS104″. In this way, the accessibility of host and VM application fileswithin file integration layer 182 of host OS 104″ eliminates the needfor the user to open and navigate separate windows in the hostenvironment that represents the desktop of each VM by which he/sheinteracts with any associated guest OS applications. When an applicationfile is selected by the user the file integration layer 182 provides themechanism for identifying whether the given application file isassociated with a host or VM application. File integration layer 182then communicates to either host OS 104″ or VMM 104′, respectively, totake the necessary action to interact with the user-selectedapplication.

As a result, the user is provided a user-friendly, automated, seamlessmechanism between, for example, host OS 104″, VM A 108, and VM B 110,which thus provides the visual appearance of all guest OS applicationfiles that exist and execute in the host environment. Application A1116, application A2 118, and application B1 120 may be either legacy ormodern applications; thus, this embodiment of the present inventionprovides a method of visually integrating an application of a legacy OS(e.g., MS-DOS, Windows 3.X, Windows 95, Windows 98, Windows Me, WindowsNT, and Windows 2000) within a host environment, such as Windows XP.Furthermore, this embodiment of the present invention allows thepossibility of multiple applications on multiple OSes, respectively, torun simultaneously and with the appearance of running in the hostenvironment.

The operation of the system of FIG. 8 is described in reference to FIG.9, which is a flowchart that illustrates a method 200 of providing andusing an application file in a host environment for accessing a guestfile tree associated with a VM and visually displaying it in the nativehost environment. At step 202, the method first comprises theinstallation of an application file for each existing host and VMapplication. Consequently, the virtual machine's desktop is no longervisible. As a result, the VM application files appear alongside andinterspersed with the host computer system's application files and allare visible and accessible to the user in the “My Computer” or “Explore”windows of the host environment of host OS 104″. Furthermore, theindividual VM application files appear alongside and interspersed with,potentially, application files from other VMs that are runningsimultaneously. At step 204, the user selects a host or VM applicationto interact with, by clicking on its associated application file. Forexample, to interact with application H1 135 of host OS 104″ the userclicks on the application file H1 184. Similarly, to interact withapplication A1 116 of guest OS A 112 the user clicks on the applicationfile A1 186.

At step 206, the selected application file communicates a request tointeract with its associated application through file integration layer182 of host OS 104″, which subsequently determines (at step 208) whetherthe application is a host or VM application. At step 210, if at step 208it is determined that the request is a VM application, file integrationlayer 182 communicates to VMM 104′ to launch a VM with its associatedguest OS, such as VM A 108 and guest OS A 112 or VM B 110 and guest OS B114. At step 212, the guest OS launches the VM application, such asguest OS A 112 launching application A1 116 or guest OS B 114 launchingapplication B1 120. The application subsequently executes and ispresented visually to the user as though the application were running inthe host environment, even though it is actually executing on a VM. Atstep 214, if at step 208 it is determined that the request is a hostapplication, such as application file H1 184 requesting to interact withapplication H1 135, file integration layer 182 communicates to host OS104″ to interact with the host application.

The seamless software integration systems and methods described in FIGS.4, 5, 6, and 7 that relate to VM A 108 and guest OS A 112 or VM B 110and guest OS B 114 are exemplary and equally applicable to any other VMand guest OS. The seamless software integration systems and methodsdescribed in FIGS. 4, 5, 6, and 7 are not limited to a standalonecomputer system; they may also be generally applied to a virtual networksystem.

For certain additional embodiments, files in the VM environment areautomatically loaded by an application in the host environment oralternatively files in the host environment are automatically loaded byan application in the VM environment. For example, the user clicks on aWord 97 document residing upon the local physical hard drive of thenative host environment. The native OS, such as Word XP, is aware that aWord 97 document runs better in a Word 97 application running in Windows95. Furthermore, the native OS is aware that there is a VM alreadyexecuting that happens to have a Word 97 application loaded thereon. Sorather than the native OS performing the default operation, where theWord 97 document is launched in the native host environment (Word XP),knowing from the metadata that the file is a Word 97 file, the native OSopens the file using the Word 97 application running on a VM, The Word97 application will run more robustly in the legacy VM environment thenin the native environment as there may be inconsistencies between Word97 and Word XP.

The general steps of launching a legacy file, for example, a Word 97document residing upon the local hard drive of the native OS running,for example, Windows XP is as follows:

-   -   1. The user selecting the Word 97 document in the native OS;    -   2. The host OS loading a Windows 95 VM;    -   3. The VMM loading a Word 97 application on the Windows 95 VM;    -   4. The VMM then gaining access to the host OS and files by        reaching across to the host environment via internal networking;    -   5. The VM loading the content of the Word 97 document file into        the VM environment; and    -   6. The VMM promoting the display of the Word 97 document back to        native OS.

The general steps of launching a modern file, for example, a Word XPdocument residing upon the VHD of a VM running, for example, Windows 95is as follows:

-   -   1. The user selecting the Word XP document on a VHD of a VM        running a legacy OS, such as Windows 95;    -   2. The VMM kicking out of the VM and into the host environment;    -   3. The VMM then gaining access to the host OS applications by        reaching across to the host environment via internal networking;    -   4. The host loading the content of the Word XP document file        into the native host environment; and    -   5. The host promoting the display of the Word XP document file        into the native OS.

In addition to the foregoing, various additional embodiments of thepresent invention are directed to similarly integrating components of aguest menu bar into the host menu bar, as well as portions of the guestOS start menu into the host OS start menu, and so on and so forth.

CONCLUSION

The various systems, methods, and techniques described herein may beimplemented with hardware or software or, where appropriate, with acombination of both. Thus, the methods and apparatus of the presentinvention, or certain aspects or portions thereof, may take the form ofprogram code (i.e., instructions) embodied in tangible media, such asfloppy diskettes, CD-ROMs, hard drives, or any other machine-readablestorage medium, wherein, when the program code is loaded into andexecuted by a machine, such as a computer, the machine becomes anapparatus for practicing the invention. In the case of program codeexecution on programmable computers, the computer will generally includea processor, a storage medium readable by the processor (includingvolatile and non-volatile memory and/or storage elements), at least oneinput device, and at least one output device. One or more programs arepreferably implemented in a high level procedural or object orientedprogramming language to communicate with a computer system. However, theprogram(s) can be implemented in assembly or machine language, ifdesired. In any case, the language may be a compiled or interpretedlanguage, and combined with hardware implementations.

The methods and apparatus of the present invention may also be embodiedin the form of program code that is transmitted over some transmissionmedium, such as over electrical wiring or cabling, through fiber optics,or via any other form of transmission, wherein, when the program code isreceived and loaded into and executed by a machine, such as an EPROM, agate array, a programmable logic device (PLD), a client computer, avideo recorder or the like, the machine becomes an apparatus forpracticing the invention. When implemented on a general-purposeprocessor, the program code combines with the processor to provide aunique apparatus that operates to perform the indexing functionality ofthe present invention.

While the present invention has been described in connection with thepreferred embodiments of the various figures, it is to be understoodthat other similar embodiments may be used or modifications andadditions may be made to the described embodiment for performing thesame function of the present invention without deviating there from. Forexample, while exemplary embodiments of the invention are described inthe context of digital devices emulating the functionality of personalcomputers, one skilled in the art will recognize that the presentinvention is not limited to such digital devices, as described in thepresent application may apply to any number of existing or emergingcomputing devices or environments, such as a gaming console, handheldcomputer, portable computer, etc. whether wired or wireless, and may beapplied to any number of such computing devices connected via acommunications network, and interacting across the network. Furthermore,it should be emphasized that a variety of computer platforms, includinghandheld device operating systems and other application specifichardware/software interface systems, are herein contemplated, especiallyas the number of wireless networked devices continues to proliferate.Therefore, the present invention should not be limited to any singleembodiment, but rather construed in breadth and scope in accordance withthe appended claims.

Finally, the disclosed embodiments described herein may be adapted foruse in other processor architectures, computer-based systems, or systemvirtualizations, and such embodiments are expressly anticipated by thedisclosures made herein and, thus, the present invention should not belimited to specific embodiments described herein but instead construedmost broadly. Likewise, the use of synthetic instructions for purposesother than processor virtualization are also anticipated by thedisclosures made herein, and any such utilization of syntheticinstructions in contexts other than processor virtualization should bemost broadly read into the disclosures made herein.

What is claimed:
 1. A method for integrating a virtual machine with ahost operating system, said virtual machine comprising a guest operatingsystem and at least one application for execution on said guestoperating system, said method comprising providing an interface in thehost operating system via a host display window by which an end-userselects for execution an application that is native to a guest operatingsystem and which, upon operation of said interface, leads to theexecution of said application in said guest operation system running onsaid virtual machine.